This invention is generally directed to imaging members, and more specifically, the present invention is directed to multilayered photoconductive imaging members with a hole blocking layer comprised, for example, of a suitable hole blocking, or undercoat layer component of, for example, an electron transport component, such as n-butyl 9-dicyanomethylenefluorene-4-carboxylate (BCFM), 2-ethylhexyl 9-dicyanomethylenefluorene-4-carboxylate (2EHCFM), 9-dicyanomethylenefluorene-4-carboxylic acid (CFM), chemically grafted onto, for example, particles, such as titanium oxide, like TiO2, tin oxide, zinc oxide, zinc sulfide, zirconium oxide and similar metal oxides and sulfides, and the like, and wherein the weight ratio of electron transport to the particles can vary, for example from about 1/1000 to about 30/100. The blocking layer enables, for example, additional pathways for electron transport thereby allowing excellent electron transport and low residual voltages, Vr; thicker hole blocking or undercoat layers, and which thicker layers permit excellent resistance to charge deficient spots, or undesirable plywood, and increase the layer coating robustness; acceptable cycling characteristics and environmental stability; and wherein honing of the supporting substrates is eliminated thus permitting, for example, the generation of economical imaging members. The hole blocking layer is preferably in contact with the supporting substrate and is preferably situated between the supporting substrate and the photogenerating layer comprised of photogenerating pigments, such as those illustrated in U.S. Pat. No. 5,482,811, the disclosure of which is totally incorporated herein by reference, especially Type V hydroxygallium phthalocyanine.
The imaging members of the present invention in embodiments exhibit excellent cyclic/environmental stability, and substantially no adverse changes in their performance over extended time periods since the imaging members can comprise a mechanically robust and solvent thick resistant hole blocking layer enabling the coating of a subsequent photogenerating layer thereon without structural damage, and which blocking layer can be easily coated on the supporting substrate by various coating techniques of, for example, dip or slot-coating. The aforementioned photoresponsive, or photoconductive imaging members can be negatively charged when the photogenerating layer is situated between the hole transport layer and the hole blocking layer deposited on the substrate.
Processes of imaging, especially xerographic imaging and printing, including digital, are also encompassed by the present invention. More specifically, the layered photoconductive imaging members of the present invention can be selected for a number of different known imaging and printing processes including, for example, electrophotographic imaging processes, especially xerographic imaging and printing processes wherein charged latent images are rendered visible with toner compositions of an appropriate charge polarity. The imaging members as indicated herein are in embodiments sensitive in the wavelength region of, for example, from about 500 to about 900 nanometers, and in particular from about 650 to about 850 nanometers, thus diode lasers can be selected as the light source. Moreover, the imaging members of this invention are useful in color xerographic applications, particularly high-speed color copying and printing processes.